1. Field of the Invention
The present invention relates to a lamp unit for a vehicle using a light emitting element such as a light emitting diode as a light source.
2. Description of the Related Art
A related art lamp unit for a vehicle using a light emitting diode as a light source has been employed. For example, JP-A-2002-50214 describes a lamp unit for a vehicle having a light emitting diode directed in the forward direction of the lamp unit and a light transmission (translucent) member that covers the light emitting diode from the front side thereof.
This related art lamp unit is such that light from the light emitting diode incident at the rear end portion of the translucent member thereof is introduced to the front end surface of the translucent member. Then, the light is emitted from the front end portion to irradiate the forward area of the lamp unit through a projection lens. When the translucent member described in the above-mentioned JP-A-2002-50214 is used, the utilization factor of light from the light emitting diode can be improved.
However, since the translucent member is configured in a substantially horn shape, there arise related art problems. For example, but not by way of limitation, the irradiation light from the translucent member cannot be controlled accurately, and the length of the lamp unit in the front-to-rear direction thereof (i.e., the longitudinal direction of a vehicle) becomes longer.